I've installed a mild 454 in my 34 Ford P/U. Runs great, cools great, oil pressure great. My problem is.....the 454 leaks oil somewhere in the rear and at highway speed it slings it out each side and undercoats the truck with oil. It leaks approx 1/2 quart in 80 miles of highway driving. We just pulled the motor and see no ovious leaks but the whole bell housing area is soaked with oil. Rear main Seal? Valve covers are sealed great, intake is sealed great. And advice will be appreciated. Help! Gary p.s. I run a big breather on the passenger valve cover and a pcv on the other.